In Worth County we have cotton that was planted from the end of March through now, with cotton planting continuing. Following is some timely information regarding irrigation in cotton from Wesley Porter, Extension Precision Ag and Irrigation Specialist, Cale Cloud, Extension Water Agent, and David Hall, Extension Water Educator.
Most people have been delayed in their cotton planting due to excessively wet conditions from the heavy rainfalls we have been receiving during the month of April. Most of the cotton should be planted during early- to mid- May. Similar to peanut, cotton does not require very much irrigation during the first month or so of growth and in some cases if adequate rainfall is received cotton can go up to squaring and even bloom without additional irrigation applications as exhibited by the red box and water use curve below in Figure 1. However, if it gets hot and dry again like it did during late March and May of 2019 you may need to apply a small irrigation application either weekly or potentially a few times per week. The red box below represents cotton water requirements the first five weeks after planting. Keep a track of rainfall and temperature, your irrigation efficiency (typically around 65-70% for high pressure systems and 80-90% for low pressure systems), and make irrigation applications accordingly. Keep in mind that the water requirement below is irrigation plus rainfall, and the weekly water requirement recommendation was developed based on a historical average of evapo-transpiration. So, your actual water/irrigation requirement may vary slightly based on weather conditions and rainfall during the growing season. For a more in-depth irrigation recommendation it is suggested that you look into implementing either a computer scheduling model either online or via a Smartphone App, or soil moisture sensors.
UGA Extension has developed a quick and easy irrigation scheduling guide that is laminated and contains the four major row crops grown in Georgia. The guide can be downloaded at:
If we can help you, please contact us at the Worth County Extension Office at 229-776-8216.